This is a competing renewal application of a three year two-stage epidemiologic study of the frequency of and risk factors for DSM-III-R major depressive disorder (MDD) and suicidal behaviors in young adolescents. The proposed continuation is designed to: (1) follow the original middle school sample of 3,200 students through high school; (2) obtain data on family history of psychiatric disorder; and (3) collect data on social and environmental risk factors. Specific objectives are: (1) To study the prevalence, incidence, and course of MDD in the sample of 7th and 8th graders as these subjects progress from the 9th through 12th grades (i.e., all subjects will be followed until they have completed high school); (2) To concomitantly investigate the frequency and course of depressive symptoms, suicidality and comorbidity of MDD; (3) To investigate the relationship between a family history of psychiatric disorder and MDD or suicidal behaviors in adolescents; (4) To study the relationship of specific types of life events and specific components of social-family environment to MDD and suicidal behaviors. In the first stage data will be collected in the schools via self-administered written questionnaires which include: (1) The Center for Epidemiological Studies Depression Scale (CES-D); (2) a suicide subscale; (3) a Life Events schedule; and (4) the Family Adaptability and Cohesion Evaluation Scales. In the second stage all students interviewed during the first three years (1986-1989) of the study (i.e., those subjects who had previously attained high CES-D or suicide scores as well as the 10% random sample of those receiving low scores) and a new random sample of subjects who had low CES-D or suicide scores in the past but now screen high will be referred for diagnostic evaluation. The diagnostic evaluation will consist of a structured interview of the child and his parent utilizing the Kiddie Schedule for Affective Disorders and Schizophrenia (both lifetime and present versions), the substance use disorders scales, the Psychosocial Schedule for School-Age Children and the Family History-Research Diagnostic Criteria instrument. Diagnosis will be made utilizing the DSM-III-R criteria. Children diagnosed as having psychiatric disorder will be offered treatment.